.box{
    width: 338px;
    height: 50px;
    transition: all 1s;
    overflow: hidden;
    text-align: center;
    line-height: 50px;
    color: rgb(228, 94, 94);
    border-radius: 5px;
    background: aqua;
}
.box:hover{
    height: 251px;  
}
.a{
    width: 338px;
    height: 50px;
    background-color: aqua;
    border-radius: 5px;
    }   
.b{
    width: 338px;
    height: 50px;
    border-top: 1px solid wheat;
    border-radius: 5px;
    background-color: #409eff;
}

